Treatment of hydrocarbon oils



Aug. 7- 'J. c. MORRELL 2,089,658

TREATMENT OF HYDROCARBON OILS Filed April 11, 1932 CONDENSER FURNACE l8 RECEIVER TOPPING AND F RACTIONATING FURNACE 4O INVENTOR JACQUE C. MORRELL Patented Aug. 10, 1937 UNETED STATES PATENT OFFICE TREATMENT OF HYDROCARBON OILS ware Application April 11, 1932, Serial No. 604,405

1 Claim.

This invention relates to the treatment of hydrocarbon oils and more particularly refers to an improved process and apparatus for topping crude petroleum and simultaneously subjecting 5 various selected components thereof to independently controlled conversion conditions together with selected intermediate conversion products of the process of similar boiling range.

The primary objects of the present invention are to separate a crude petroleum, containing a substantial proportion of materials within the boiling range of gasoline, into said gasoline and higher boiling components, subjecting the latter to cracking for the production of additional yields of motor fuel, further separate both the cracked and straight-run gasoline into relatively low boiling components of good antiknock value and higher boiling components of inferior antiknock value, subject the motor fuel components of inferior antiknock Value to independently controlled conversion conditions for the production of lower boiling products of improved antiknock value, subject the insufiiciently converted intermediate products of the operation to further conversion for the production of additional yields of motor fuel and recover as the final light distillate product a low boiling motor fuel comprising a blend of straight-run and cracked products of high antiknock value. By use of the principles of the present invention all of these objects are accomplished simultaneously in a single unified system of relatively simple form.

A more specified embodiment of the invention may comprise subjecting crude oil to heating and fractionationwhereby to vaporize and separate its gasoline components from its heavier components, subjecting said heavier components, comprising topped crude, to cracking temperature at super-atmospheric pressure in a heating '40 coil, introducing the heated oil into an enlarged stantial proportion of material within the boiling range of gasoline, but of poor antiknock value, subjecting said intermediate reflux condensate to independently controlled conversion conditions in a separate heating coil and introducing the heated material into said reaction chamber, sep- 5 arately removing from the fractionator of the cracking system a higher boiling reflux condensate and returning the same to further cracking together with the topped crude oil.

The attached diagrammatic drawing is given 10 for the purpose of illustrating one specific form of apparatus in which the process of the present invention may be practiced. Crude oil, comprising the raw oil charging stock for the system, is supplied through line i and valve 2 to pump 3, 10 from which it is fed through line 4, valve 5, heating element 6, line I and valve 8 into topping or fractionating column 9. Heating element 6 is located in a furnace E0 of any form suitable for supplying sufiicient heat to the oil passing 0 through heating element 6 to effect its substantial subsequent vaporization in column 9, preferably without appreciable conversion of the oil. Relatively light and relatively heavy components of the crude are arbitrarily separated by frac- 25 tionation in column 9, vapors from which may, if desired, be drained off through line H controlled by valve l2 and be separately condensed and collected by means not shown.

The relatively heavy components of the crude 30 are withdrawn from the lower portion of column 9 through line H and valve [2 to pump I3, from which they are fed through line M, valve [5 and line IE to heating elements I! for conversion. Heating element I1 is located in a furnace l8 of 35 any suitable form and the oil supplied thereto is heated to the desired conversion temperature, preferably at substantial superatmospheric pressure. The heated materials from heating element ll'pass through line I9, valve 20 and line 2| 40 into reaction chamber 22.

Chamber 22 is also preferably maintained at substantial superatmospheric pressure and separation is effected in this zone between the vaporous and non-vaporous conversion products of the system. Residual oil, when such is produced, may be withdrawn from the reaction chamber through line 23 and valve 24 to storage or to any further desired treatment. However, when desired, conditions may be regulated in chamber 22 to cause reduction of the residual material remaining in chamber 22 to substantially dry coke, in which case it is allowed to accumulate within the reaction chamber until the operation of the chamber is discontinued. When coking of the residual oil is employed a plurality of coking chambers similar to chamber 22 but not shown, may be utilized, if desired, and may be operated either alternately or simultaneously to provide greater space for the deposition of coke and thus prolong the operating cycle.

Vapors from reaction chamber 22 pass through line 25 and valve 26 into fractionator 21, wherein their relatively heavy insuificiently convertedcomponents, roughly corresponding in boiling range to heavy components of the crude, are condensed and withdrawn from the lower portion of the fractionator through line 28 and valve 29 to pump 39. Pump 30 supplies the primary or heavy reflux condensate from fractionator 21 through line l6 and valve 3| to heating element I! for further conversion together with the heavy components of the crude oil supplied to this zone, as already described.

Simultaneous with the introduction of vapors from chamber 22 into fractionator 2'! vapors from column 9, comprising the relatively light components of the crude, are supplied to the same fractionator through line 32 and valve 33. The intermediate components of the vapors introduced into fractionator 2'|,'from both sources, which boil below the initial boiling point of the primary or heavy reflux condensate and above the end boiling point of the desired final motor fuel product, are condensed in the fractionator as secondary or light reflux condensate and may be withdrawn therefrom as a side stream through line 34 and valve 35 to pump 35, from which they are fed through line 31 and valve 38 to heating element 39.

Heating element 39 is located in a furnace 40 of suitable form and the oil supplied to this zone is heated to a conversion temperature, preferably more severe than that employed in heating ele- 40 ment I! and preferably at substantial superatknown means not illustrated'in the drawing.

vaporous products from theupper portion of fractionator 21, comprising the desired gasoline components of the crude, cracked motor fuel and uncondensable gas, are withdrawn through line 43 and valve '44 to condensation and cooling in condenser 45, distillate and uncondensable gas from which passes through line 46 and valve 4'! to be collected in receiver 48. Uncondensable gas may be released from the receiver through line 49 and Valve 59. Distillate may be withdrawn through line 5! and valve 52. A portion of the distillate may, when desired, be recirculated, by well known means not illustrated, from receiver 48 to the upper portion of fractionator 2! to assist fractionation and to maintain the desired vapor outlet temperature from this zone.

It is, ofcourse, within the scope of the inven tion to. preheat, and top the crude oil by means of heat recovered from within the system or other well known means not illustrated in the drawing. For example, the crude oil'may be preheated by indirect contact with hot. vaporous or liquid final or intermediate products of the system, prior to its introduction'into the topping column. 'This method of preheating may be used either in conjunction with heating coil 6 or may obviate the use of this heating coil. Another modification of the operation, not shown in the attached drawing, but which is entirely within the scope of the invention, comprises introducing the crude oil, in either heated or nonheated state directly into fractionator 21 of the cracking system wherein it comes into direct contact with the hot vaporous conversion products and whereby it is separated into three fractions,

one comprising material boiling within the range of desired final light product and being condensed and collected therewith, another fraction boiling within the range of light reflux condensate and a third fraction boiling within the range of the heavy reflux condensate, each of which latter fractions are subjected to conversion together with the components of the reflux condensate of similar boiling range.

The topping portion of the system is preferably operated at substantially atmospheric pressure, although superatmospheric pressures up to pounds or thereabouts, per square inch, may be employed in the'heating element when desired and may be either reduced or substantially equalized in the topping and fractionating column. Conversion conditions employed in the primary heating element to which heavy components of the crude and primary refluxcondensate from the fractionator of the cracking system are supplied, may utilize temperatures of the order of 800 to 950 F., and superatmospheric pressures ranging from 100 to 500 pounds or more per square inch. Temperatures of the orderof 900 to 1050 F. and superatmospheric pressures of the order of 200 to 800 pounds or more, per square inch, may be employed in the secondary heating element. The pressures employed in the reaction chamber may be substantially equalized with or somewhat reduced relative to that em- 3,.

ployed in the heating element utilizing the lowest pressure. The fractionating, condensing and col-' lecting portions of the system may be operated at substantially the same or reduced pressure relative to that employed in the reaction chamber but, preferably, at a pressure no greater than that employed in the topping column.

, As a specific example of the operation of the process of the present invention, a43 A. P. I.

gravity Mid-continent crude containing some 45 percent of material boiling up to 437 F. is the raw oil charging stock for the system. Vapors from the topping operation having an end-boiling point of approximately 550 F. are supplied to the fractionator of thecracking system. The topped crude and the heavy reflux condensate from the cracking operation are subjected to conversion at a temperature of approximately 900 F. under a pressure of approximately 300 pounds per square inch. Materials from both the cracking and topping operations boiling between approximately, 350 and 550 F. are separately subjected toa conversion temperature of about 950 F. at a super-atmospheric pressure of approximately 500 pounds per square inch and are introduced into the reaction chamber. Non-residuum operation is employed in the reaction zone. A blend of straight-run and cracked motor fuel having an end-boiling point of approximately 350 F. is collected as the final distillate product of the system. 7

This operation may yield, per barrel of crude oil charging stock, about 75 percent of motor fuel having an antiknock value equivalent to an octane number of approximately 76, about 40 pounds of coke and about 750 cubic feet of uncondensable gas.

I claim as my invention:

A process for producing anti-knock motor fuel distillate which comprises fractionating cracked vapors in a fractionating zone to condense insufiiciently cracked fractions thereof as reflux condensate, simultaneously topping crude oil containing a substantial quantity of natural gasoline fractions of relatively low anti-knock value and commingling the natural gasoline vapors with cracked vapors in the fractionating zone, condensing from the commingled vapors a liquid fraction containing a substantial quantity 15 of hydrocarbons boilingwithin the gasoline range,

subjecting the reflux condensate in admixture with fractions of the crude heavier than gasoline to cracking conditions of temperature and pressure, independently heating said liquid fraction to a higher cracking temperature under conditions such as to increase the anti-knock value of the gasoline hydrocarbons contained therein, introducing vapors evolved by such heating of the reflux condensate, the fractions of the crude heavier than gasoline and said liquid fraction into the fractionating zone to constitute said cracked vapors, and removing and condensing the gasoline vapors uncondensed in the fractionating zone.

JACQUE C. MORRELL. 

